Selective deficiency of IgA

Definition

Selective deficiency of IgA is the most common immune deficiency disorder. People with this disorder have a low or absent level of a blood protein called immunoglobulin A.

Alternative Names

IgA deficiency; Immunodepressed - IgA deficiency; Immunosuppressed - IgA deficiency; Hypogammaglobulinemia - IgA deficiency; Agammaglobulinemia - IgA deficiency

Causes

IgA deficiency is usually inherited, which means it is passed down through families. However, there are also cases of drug-induced IgA deficiency.

It may be inherited as an autosomal dominant or autosomal recessive trait. It is usually found in people of European origin. It is less common in people of other ethnicities.

Symptoms

Many people with selective IgA deficiency have no symptoms.

If a person does have symptoms, they may include frequent episodes of:

• Bronchitis (airway infection)
• Chronic diarrhea
• Conjunctivitis (eye infection)
• Gastrointestinal inflammation, including ulcerative colitis, Crohn disease, and a sprue-like illness
• Mouth infection
• Otitis media (middle ear infection)
• Pneumonia (lung infection)
• Sinusitis (sinus infection)
• Skin infections
• Upper respiratory tract infections

Other symptoms include:

• Bronchiectasis (a disease in which the bronchial tubes in the lungs become damaged and enlarged)
• Asthma without a known cause

Exams and Tests

There may be a family history of IgA deficiency. Tests that may be done include:

• IgG subclass measurements
• Quantitative immunoglobulins
• Serum immunoelectrophoresis

Treatment

No specific treatment is available. Some people gradually develop normal levels of IgA without treatment.

Treatment involves taking steps to reduce the number and severity of infections. Antibiotics are often needed to treat bacterial infections.

Immunoglobulins are given through a vein or by injection to boost the immune system.

Autoimmune disease treatment is based on the specific problem.

Note: People with complete IgA deficiency may develop anti-IgA antibodies if given blood products and immunoglobulins. This may lead to allergies or life-threatening anaphylactic shock. However, they can safely be given IgA-depleted immunoglobulins.

Outlook (Prognosis)

Selective IgA deficiency is less harmful than many other immunodeficiency diseases.

Some people with IgA deficiency will recover on their own and produce IgA in larger quantities over a period of years.

Possible Complications

Autoimmune disorders such as rheumatoid arthritis, systemic lupus erythematosus, and celiac sprue may develop.

People with IgA deficiency may develop antibodies to IgA. As a result, they can have severe, even life-threatening reactions to transfusions of blood and blood products.

When to Contact a Medical Professional

If you have an IgA deficiency, be sure to mention it to your health care provider if immunoglobulin or other blood-component transfusions are suggested as a treatment for any condition.

Prevention

Genetic counseling may be of value to prospective parents with a family history of selective IgA deficiency.

References

Cunningham-Rundles C. Primary immunodeficiency diseases. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 236.

Sullivan KE, Buckley RH. Primary defects of antibody production. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 150.